An informal survey of real estate agents over at the Chronicle found that a "parking spot attached to a condo or home could be worth 100K or more, particularly in notoriously hard-to-park areas with older buildings that are less likely to have parking, like Telegraph Hill, Nob Hill or North Beach." To be fair, this four bedroom condo on Telegraph Hill is listed at $5.3 million—and this house at $16 million. With prices like that, an extra $100 grand is a rounding error. (Out in the Excelsior or the Sunset, a parking space will run you only an additional $25 to $60 thousand.)

At least anecdotally, the value of parking spaces may be declining as the prestige of owning a car also does. The Chron quotes one real estate agent as saying, "With car sharing services like Zipcar and taxi alternatives such as Uber and Lyft, plus more job opportunities to work in S.F. and corporate bus shuttles, and biking becoming even more popular, people depend a bit less on owning their own car [...] I hear, more often than before, people saying they do not own a car, or they do not use their car as much as before."